diff options
Diffstat (limited to 'system/xen/xsa/xsa301-master-2.patch')
| -rw-r--r-- | system/xen/xsa/xsa301-master-2.patch | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa301-master-2.patch b/system/xen/xsa/xsa301-master-2.patch new file mode 100644 index 0000000000000..baedc9c29751f --- /dev/null +++ b/system/xen/xsa/xsa301-master-2.patch @@ -0,0 +1,92 @@ +From 3b896936f7505e929dd869d14afcb185d0ee75f8 Mon Sep 17 00:00:00 2001 +From: Julien Grall <julien.grall@arm.com> +Date: Tue, 15 Oct 2019 17:10:41 +0100 +Subject: [PATCH 2/3] xen/arm: p2m: Avoid off-by-one check on + p2m->max_mapped_gfn + +The code base is using inconsistently the field p2m->max_mapped_gfn. +Some of the useres expect that p2m->max_guest_gfn contain the highest +mapped GFN while others expect highest + 1. + +p2m->max_guest_gfn is set as highest + 1, because of that the sanity +check on the GFN in p2m_resolved_translation_fault() and +p2m_get_entry() can be bypassed when GFN == p2m->max_guest_gfn. + +p2m_get_root_pointer(p2m->max_guest_gfn) may return NULL if it is +outside of address range supported and therefore the BUG_ON() could be +hit. + +The current value hold in p2m->max_mapped_gfn is inconsistent with the +expectation of the common code (see domain_get_maximum_gpfn()) and also +the documentation of the field. + +Rather than changing the check in p2m_translation_fault() and +p2m_get_entry(), p2m->max_mapped_gfn is now containing the highest +mapped GFN and the callers assuming "highest + 1" are now adjusted. + +Take the opportunity to use 1UL rather than 1 as page_order could +theoritically big enough to overflow a 32-bit integer. + +Lastly, the documentation of the field max_guest_gfn to reflect how it +is computed. + +This is part of XSA-301. + +Reported-by: Julien Grall <Julien.Grall@arm.com> +Signed-off-by: Julien Grall <julien.grall@arm.com> +Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> +--- + xen/arch/arm/p2m.c | 6 +++--- + xen/include/asm-arm/p2m.h | 5 +---- + 2 files changed, 4 insertions(+), 7 deletions(-) + +diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c +index d0045a8b28..8d20d27961 100644 +--- a/xen/arch/arm/p2m.c ++++ b/xen/arch/arm/p2m.c +@@ -1041,7 +1041,7 @@ static int __p2m_set_entry(struct p2m_domain *p2m, + p2m_write_pte(entry, pte, p2m->clean_pte); + + p2m->max_mapped_gfn = gfn_max(p2m->max_mapped_gfn, +- gfn_add(sgfn, 1 << page_order)); ++ gfn_add(sgfn, (1UL << page_order) - 1)); + p2m->lowest_mapped_gfn = gfn_min(p2m->lowest_mapped_gfn, sgfn); + } + +@@ -1572,7 +1572,7 @@ int relinquish_p2m_mapping(struct domain *d) + p2m_write_lock(p2m); + + start = p2m->lowest_mapped_gfn; +- end = p2m->max_mapped_gfn; ++ end = gfn_add(p2m->max_mapped_gfn, 1); + + for ( ; gfn_x(start) < gfn_x(end); + start = gfn_next_boundary(start, order) ) +@@ -1641,7 +1641,7 @@ int p2m_cache_flush_range(struct domain *d, gfn_t *pstart, gfn_t end) + p2m_read_lock(p2m); + + start = gfn_max(start, p2m->lowest_mapped_gfn); +- end = gfn_min(end, p2m->max_mapped_gfn); ++ end = gfn_min(end, gfn_add(p2m->max_mapped_gfn, 1)); + + next_block_gfn = start; + +diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h +index 89f82df380..5fdb6e8183 100644 +--- a/xen/include/asm-arm/p2m.h ++++ b/xen/include/asm-arm/p2m.h +@@ -36,10 +36,7 @@ struct p2m_domain { + /* Current Translation Table Base Register for the p2m */ + uint64_t vttbr; + +- /* +- * Highest guest frame that's ever been mapped in the p2m +- * Only takes into account ram and foreign mapping +- */ ++ /* Highest guest frame that's ever been mapped in the p2m */ + gfn_t max_mapped_gfn; + + /* +-- +2.23.0 + |